This invention relates to a rotary cutting unit for use on a mower, preferably a mower in which a plurality of spaced and staggered cutting units collectively cut a swath of grass as the riding mower is operated.
Riding mowers are known which carry a plurality of rotary cutting units for cutting a relatively wide swath of grass. For example, the Ransomes AR 250 is a five-plex rotary mower having three, front rotary cutting units arranged in a first row and two, rear rotary cutting units arranged in a second row. The front rotary cutting units are arranged in advance of the front wheels of the mower while the rear rotary cutting units are arranged between the front and rear wheels of the mower. The rear cutting units are further arranged to cover the gaps between the front cutting units. Thus, as the mower is driven forwardly and the cutting units are operated, the five cutting units cut a single swath of grass.
While such cutting units are effective in cutting a relatively wide swath of grass with each pass, the cut grass swath exhibits streaking, at least in certain grass conditions. Such streaking comprises a row or streak of uncut grass or of grass that is not cut as evenly and uniformly as the rest of the grass in the cut path. The Applicant has noticed such streaking occurring between the multiple rotary cutting units in a mower of this type, especially when the mower is turning or is traversing slopes. The streaks often occur generally along the line where one side of one of the front cutting units overlaps with a side of one of the rear cutting units. The presence of such streaks is obviously not aesthetically pleasing and is a disadvantage to such a mower having rotary cutting units.
Each cutting unit in a mower of this type carries a combination of rollers and wheels for allowing the cutting unit to roll over the ground as the mower moves forwardly. In the known Ransomes AR 50 mower, each cutting unit is supported at the rear by a full length rear roller. At the front, each cutting unit is supported by two caster wheels adjacent the front corners of the unit. The caster wheels are supported for turning about vertical pivots in a well known manner.
While the caster wheel/rear roller structure adequately supports the cutting unit for rolling on the ground, the use of caster wheels has some disadvantages. In order to support the caster wheels for free pivoting about their vertical pivots, the wheels must be set fairly far forwardly of the front of the cutting unit to allow for mounting of the pivot structure and to allow the caster wheels to swing about their vertical pivots without hitting the front of the unit. Mounting the caster wheels far enough forwardly to allow for proper pivoting of the wheels hinders or interferes with the ability of the unit to follow the ground contour and puts the support provided by the front caster wheels further forwardly relative to the blade than would be desirable. A more compact way of supporting the front of the cutting unit for rolling over the ground would be advantageous.
One aspect of this invention is directed to reducing or eliminating streaking between adjacent cutting units. This aspect is provided in a mower which comprises a traction vehicle. A plurality of cutting units are carried on the traction vehicle which cutting units collectively cut a swath of grass as the traction vehicle is operated. The cutting units comprise rotary-type cutting units each having at least one cutting blade which is rotated in a substantially horizontal cutting plane. In addition, the cutting units each include a cutting deck which includes cut-outs at each front corner thereof in which the cutting blade is exposed to uncut grass approaching each front corner of each cutting deck.
Another aspect of this invention relates to ground engaging rollers for the cutting deck. This aspect is provided in a mower comprising a traction vehicle. At least one cutting unit is carried on the traction vehicle. At least two ground engaging rollers are carried on the cutting unit with the rollers being laterally spaced apart relative to one another. Each roller has an ovate shape.